The Palaeozoic which preceded the Mesozoic has ended with the biggest extinction event ever. 70% of species living on land and 95% of marine species died out. It was the only extinction that seriously affected insects.
Only five genera of the Trilobites still existed at the end of the Permian: Kathwaia capitorosa (A-B), Acropyge brevica (C-D), Pseudophillipsia (E), Paraphillipsia (F-G), Cheiropyge (H). But then they went extinct as well.

(Owens, R. M. 2003)

Pseudophillipsia

Body length: 4–5 cm
Fed on detritus on the seabed.

Hibbertopterus permianus

“sea Scorpion”
Body length: approx. 2.5 m long
Lived in warm, coastal waters.

Pareiasaurus serridens

Herbivorous reptile, which had teeth even on his palate.
Body length: Up to 2 m in, lived on land.

Elginia mirabilis

Reptile, known only by its skull.
Body length: up to 3 m, lived on land.

Youngina capensis

Small, early reptile, similar to today's Tuatara.

Diplocaulus sp.

Amphibious, with a typical boomerang shaped head.
Body length: 1 m

Lived in swamps and rivers.

Dinogorgon rubidgei

Mammal-like reptile, predator.
Body length: approx. 2 m, lived in forests.